1. Field of the Invention
The present invention relates to a semiconductor device having a plurality of conductive patterns and to a method and apparatus for testing the device.
2. Background Art
Some semiconductor devices have a guard ring structure designed to enhance the dielectric strength of the device. The guard ring structure includes a first conductivity type layer and a plurality of annular second conductivity type regions (i.e., guard rings) formed in the first conductivity type layer. Conductive patterns are formed on the guard rings to stabilize the potential of the guard rings. More specifically, each conductive pattern is formed on a respective one of the guard rings. The conductive patterns must be insulated from one another and must be free from open circuits or breaks.
Therefore, the manufacturing process of a semiconductor device includes a test process for determining whether the conductive patterns meet these requirements. An illustrative example of such a test process is described in Japanese Laid-Open Patent Publication No. 2002-141474. This publication discloses a test process for measuring electrical characteristics of the conductive patterns. Specifically, in this process, probe needles are pressed against pads formed on portions of the conductive patterns to measure electrical characteristics of the conductive patterns. It should be noted that these pads have a large surface area to facilitate the pressing of the probe needles against the pads.
The test process described in the above patent publication requires that the conductive patterns be provided with pads. It has been found, however, that this requirement may prevent the conductive patterns from having an optimum configuration for increasing the dielectric strength of the semiconductor device, making it impossible to sufficiently increase the dielectric strength of the device.